Chapter 3: Sensory & Motor Systems - Hearing, Touch, Smell, and Taste Flashcards
The sense of hearing.
Audition.
The height of a periodic curve measured on its vertical axis.
Amplitude.
The number of cycles of a periodic wave per unit of time.
Frequency.
A unit used to express a difference in intensity between two sounds.
Decibel (dB).
A unit of sound frequency equal to one cycle per second.
Hertz (Hz).
The quality of a sound that distinguishes it from other sounds of the same pitch and volume.
Timbre.
Sound at frequencies above the range of human hearing, or higher than about 20000 Hz.
Ultrasound.
Sound at frequencies below the range of human hearing, or lower than about 20 Hz.
Infrasound.
The components that make up the ear are generally divided into three (3) parts.
- The Outer Ear
- The Middle Ear
- The Inner Ear
The visible part of the outer ear.
Pinna.
A tube-shaped structure in the outer ear that leads to the tympanic membrane.
Auditory canal.
This forms the boundary between the outer ear and middle ear.
Tympanic membrane (eardrum).
A membrane that forms the boundary between the middle and inner ears.
Oval window.
The bones of the middle ear.
Ossicles.
The first of three ossicles in the middle ear.
Malleus.
The middle of three ossicles found in the middle ear.
Incus.
The innermost of the three ossicles of the middle ear.
Stapes.
The protective restriction of the movement of the tympanic membrane and ossicles, resulting in a reduction of sound to the inner ear by a factor of 30 dB.
Acoustic reflex.
Two (2) muscles in the middle ear.
- Tensor tympani
- Stapedius
Contains two sets of fluid-filled cavities embedded in the temporal bone of the skull.
The Inner Ear.
Contains specialized receptor cells that respond to the vibrations transmitted to the inner ear; is fluid-filled.
Cochlea.
The cochlea’s three (3) parallel chambers.
- Vestibular canal
- Tympanic canal
- Apex
The part of the cochlea most distant from the oval window.
Apex.
Fluid found in the vestibular and tympanic canals of the inner ear.
Perilymph.
The fluid found in the cochlear duct.
Endolymph.
A membrane that separates the vestibular canal and the cochlear duct in the inner ear.
Reissner’s membrane.
A structure in the cochlea that separates the tympanic canal and the cochlear duct.
Basilar membrane.
A membrane covering the end of the tympanic canal.
Round window.
A structure within the cochlear duct responsible for translating vibrations in the inner ear into neural messages.
Organ of Corti.
Out of the approximately 15500 hair cells in each human inner ear, about how many of them are inner hair cells, which are the actual auditory receptors?
3500 inner hair cells.
Out of the approximately 15500 hair cells in each human inner ear, about how many of them are outer hair cells, which appear to amplify sound?
12000 outer hair cells.
Structure found in the inner ear whose axons form the auditory nerve.
Spiral ganglion.
Cortex located just below the lateral fissure in the temporal lobe that provides the initial cortical processing of auditory information.
Primary auditory cortex (Heschl’s gyrus).
Areas surrounding the primary auditory cortex in the temporal lobe that process more complex types of stimuli.
Secondary auditory cortex.
The part of the human secondary auditory cortex that specifically decodes speech.
Wernicke’s area.
A person is considered legally deaf when speech sounds equal to or less than __ dB cannot be heard.
82 dB.
A term used to refer to hearing loss resulting from problems in the outer or middle ear.
Conduction loss.
Conduction loss can result from the following.
- Buildup of wax in the ear canal
- Infections of the middle ear
- A disease known as otosclerosis
The system that provides information about the body senses, including touch, movement, pain, and temperature.
Somatosensory system.
The sensory system that provides information about the position and movement of the head.
Vestibular system.
A structure in the inner ear vestibular system that provides information about the angle of the head relative to the ground and about linear acceleration.
Otolith organ.
One of three (3) looping chambers found in the inner ear that provide information regarding the rotation of the head.
Semicircular canal.
The largest and heaviest organ of the human body.
Skin.
Two (2) basic varieties of skin.
- Hairy skin
- Glabrous, or hairless skin
Outer layers of the skin.
- Epidermis (outer)
- Dermis (inner)
Contains connective tissues and fat; found below the dermis.
Subcutaneous tissue.
A skin receptor that senses touch, pressure, or vibration.
Mechanoreceptor.
A mechanoreceptor in which the axon fibers are surrounded by a fluid-filled capsule formed of connective tissue.
Encapsulated receptor.
Responds primarily to pressure.
Meissner’s corpuscle.
Provides information about pressure and vibration.
Pacinian corpuscle.
Provides information primarily about pressure.
Merkel’s disk.
Provides information regarding stretch.
Ruffini’s ending.
A myelinated fiber that carries information about cold and sharp pain to the central nervous system.
Alpha-delta fiber.
A small, unmyelinated fiber that carries information about temperature, itch, and dull, aching pain to the central nervous system.
C fiber.
The largest fibers; carry information from the muscles.
Alpha-alpha.
Carries information from the Meissner’s corpuscles, Merkel’s disks, Pacinian corpuscles, and Ruffini’s endings toward the central nervous system.
Alpha-beta class.
The spinal pathway that carries information about touch and position to the medulla.
Dorsal column.
The pathway originating in the dorsal column nuclei and synapsing in the ventral posterior (VP) nucleus of the thalamus that is responsible for carrying information about touch and position.
Medial lemniscus.
A nerve that carries sensation from mechanoreceptors, temperature receptors, and pain receptors in the skin of the face, mouth, tongue, and the dura meter of the brain.
Trigeminal nerve (Cranial nerve V).
Occurs in the human somatosensory cortex as a result of both loss and enhancement of input.
Plasticity.
These are free nerve endings in the skin that respond to surface temperature.
Thermoreceptors.
Free nerve endings that respond to pain.
Nociceptors.
These are responsible for that sensation of a quick, sharp “ouch.”
Alpha delta fibers.
These are responsible for dull, aching types of pain sensation.
C fibers.
Both types of ascending pain fibers use _________ as their primary neurotransmitter.
Glutamate.
A group of cells in the outer gray matter of the dorsal horn that receive synapses from pain fibers.
Substantia gelatinosa.
A neurotransmitter substance associated with the sense of pain that also serves as a stimulus at some nociceptors.
Substance P.
The sense of smell.
Olfaction.
The layer in the nasal cavity containing olfactory receptors.
Olfactory epithelium.
Four (4) major categories of taste.
- Sweet
- Sour
- Salty
- Bitter
One of the five basic taste groups, characteristic of tastes found in seaweed and other “meaty or savory” elements of Asian cuisine.
Umami.
Receptors for taste are found not only in the tongue but also in other parts of the mouth.
Taste receptors.
Bumps on the tongue containing taste buds and taste receptors.
Papillae.
Small fibers extending from taste receptors.
Microvilli.
